Front and back discrimination device

Abstract

To provide a front and rear discrimination device capable of highly accurately and efficiently executing front and rear discrimination of an object.SOLUTION: A front and rear discrimination device 1 comprises: a shape sensor 21 that executes shape inspection for irradiating an inspection surface Wa selected as one of the end surfaces of an object W having front and rear end surfaces different from each other in at least one of a shape and a size with shape inspection light L1 and detecting the shape inspection light L1 reflected on the inspection surface Wa to detect a height distribution in the inspection surface Wa over a prescribed inspection region on the inspection surface Wa; a sloped introduction road 11 on which the object W is rolled on a side surface to an inspection position P at which the shape inspection can be executed by the shape sensor 21; a stop member 12 that is positioned below the slope of the introduction road 11 and that abuts against the object W rolled on the introduction road 11 and stops the rolling of the object W at the inspection position P; and a discrimination unit that discriminates which of the front and rear end surfaces the inspection surface Wa is on the basis of information about the height distribution in the inspection surface Wa acquired through the shape inspection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a front / back discriminating device, and more particularly to a front / back discriminating device for discriminating the front / back orientation of an object having front and back end surfaces that are different from each other in at least one of shape and size. [Background technology]

[0002] In the process of manufacturing metal parts and the like, it is sometimes necessary to determine which side of a part, whose front and back surfaces have different shapes and dimensions, faces. For example, when rolling a ring-shaped member made of steel produced by forging or the like, it is necessary to determine the front and back directions of the ring-shaped member, and then orient the front and back surfaces in a predetermined direction before rolling. Rolling can only be performed on a predetermined side of the front and back surfaces. If rolling is performed on the wrong side, a product having the desired shape cannot be obtained after rolling, and it may even lead to a breakdown of the rolling device.

[0003] Contact sensors have generally been used to distinguish between the front and back sides of parts. For example, Patent Document 1 discloses a method of detecting the front and back sides of a part by contacting the tip of a needle with the surface of the part and scanning the surface for a predetermined distance, thereby detecting the up and down movement of the needle with a displacement sensor. The front and back sides are determined by detecting the markings on one of the front and back sides from the up and down movement of the needle.

[0004] Optical sensors are also used to distinguish between the front and back sides of parts. In this case, the distance from the position where the sensor is installed to a point on the part is measured. The front and back sides are then determined by comparing this with the estimated values ​​for the distance to each surface. In some cases, multiple optical sensors are installed to measure the distance to multiple points on the part. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 59-206086 Summary of the Invention [Problem to be solved by the invention]

[0006] When a contact sensor is used to distinguish between the front and back of an object, as described in Patent Document 1, it is necessary to adjust the positional relationship between the object and the sensor so that the sensor makes appropriate contact with the surface of the object. In particular, if the shape or size of the object changes, significant readjustment may be required. Even when an optical sensor is used to measure the distance to a point on a part, the accuracy of the distinction may be reduced due to factors such as a misalignment between the object and the sensor.

[0007] In this way, when determining whether an object is front or back by detecting unevenness with a contact sensor or measuring distance with an optical sensor, it is important to position the object in an appropriate positional relationship with the sensor in order to obtain a sufficiently high level of accuracy. Furthermore, in a front / back discrimination device, it is often required to sequentially determine whether a large number of objects are front or back, and in such cases, it is desirable to quickly and efficiently position each object in an appropriate positional relationship with the sensor.

[0008] The problem to be solved by the present invention is to provide a front / back discriminating device that can discriminate the front / back of an object with high accuracy and high efficiency. [Means for solving the problem]

[0009] In order to solve the above problem, the front / back discrimination device of the present invention comprises: a shape sensor that performs shape inspection on an object having front and back end faces at both ends of its side that differ from each other in at least one of the shape and dimensions, by irradiating a test surface selected as one of the end faces with shape inspection light and detecting the shape inspection light reflected from the test surface to detect the height distribution on the test surface over a predetermined inspection area on the test surface; an inclined lead-in path that rolls the object on the side to an inspection position where the shape inspection by the shape sensor can be performed; a stopping member that is located below the inclination of the lead-in path and abuts against the object that has rolled on the lead-in path, stopping the rolling of the object at the inspection position; and a discrimination unit that determines whether the test surface is a front or back end face based on information on the height distribution on the inspection surface obtained by the shape inspection.

[0010] Here, the front / back discrimination device further has a displacement sensor that irradiates displacement measurement light onto multiple measurement points spaced apart on the side of the object at the inspection position and measures the distance to each of the multiple measurement points, and the discrimination unit can use information on the relationship between the distances measured by the displacement sensor to each of the measurement points when determining whether the inspection surface is a front or back end face.

[0011] The shape sensor may irradiate the inspection surface of the object at the inspection position with the shape inspection light from a direction deviated from an axis perpendicular to the inspection surface.

[0012] The object may have a cylindrical shape having a hollow portion connecting the front and back end surfaces, and the shape inspection light may be irradiated onto an area including the edge of the hollow portion.

[0013] The front / back discrimination device may further include a positioning member, located to the side of the introduction path in an area including the inspection position, that can abut against the inspection surface of the object and that has a slit through which the shape inspection light can pass, and a pressing member that is positioned opposite the positioning member across the introduction path, that is movable toward and away from the introduction path, and that can press the object, whose rolling has been stopped by the stopping member, against the positioning member by advancing toward the introduction path.

[0014] The front / back discrimination device further has two introduction control members arranged along the introduction path at a distance from each other, upstream of the inspection position of the introduction path, and the two introduction control members are capable of moving forward and backward independently from the side of the introduction path toward the introduction path, and when advanced, they abut against the side of the object rolling along the introduction path to stop the rolling of the object, and it is preferable that a distance be provided between the two introduction control members that allows only one object to be placed thereon.

[0015] The front / back discrimination device may further have an inversion unit, which may be capable of changing the orientation of the object based on the results of discrimination by the discrimination unit so that the end surfaces of the front and back face in a fixed direction.

[0016] In this case, the inversion section is provided downstream and above the stop member along the introduction path, and the introduction path is movable up and down, so that when it is moved downward, the object can be held at the inspection position, and when it is moved upward, the object can be introduced into the inversion section by rolling. [Effects of the Invention]

[0017] The front / back discrimination device according to the above invention uses a shape sensor that detects the height distribution over a predetermined inspection area on the inspection surface using light to discriminate between the front and back of the object. The shape sensor does not require contact with the object. Furthermore, the height distribution is detected not at a point on the inspection surface but over the entire inspection area spanning a predetermined range. Therefore, even if there is a certain degree of misalignment in the positional relationship between the shape sensor and the inspection surface of the object, it is possible to discriminate with high accuracy whether the inspection surface is the front or back of the object based on the information on the height distribution in the inspection area.

[0018] Furthermore, the front / back discrimination device according to the above invention is equipped with an introduction path and a stopping member, and by rolling the object under the force of gravity and bringing it into contact with the stopping member, the object can be guided to an inspection position where it can be inspected using a shape sensor. Therefore, the object can be automatically and quickly introduced to the predetermined inspection position, enabling highly accurate front / back discrimination. In particular, when discriminating between the front and back of a large number of objects sequentially, accurate introduction of the objects and front / back discrimination can be performed continuously and efficiently, allowing for efficient front / back discrimination. Furthermore, the process of discriminating between the front and back using the front / back discrimination device can be smoothly connected to the processes before and after.

[0019] Here, the front / back discrimination device further includes a displacement sensor that irradiates a plurality of measurement points spaced apart on the side surface of the object at the inspection position with displacement measurement light and measures the distance to each of the plurality of measurement points. When the discrimination unit determines whether the inspection surface is the front or back end surface, if information on the relationship between the distances measured by the displacement sensor to each of the measurement points is available, information on the positional relationship between the plurality of points on the side surface of the object obtained by the displacement sensor can be used to discriminate between the front and back surfaces, in addition to information on the height distribution of the object's end surface obtained by the shape sensor. As a result, the front / back discrimination can be performed with even higher accuracy. In particular, when a feature reflecting a difference between the front and back sides, such as a step structure caused by a difference in outer diameter between the front and back surfaces, is significantly apparent on the side surface, the accuracy of the front / back discrimination can be effectively improved by using the results of the measurement of the side surface by the displacement sensor.

[0020] When a shape sensor irradiates the inspection surface of an object at the inspection position with shape inspection light from a direction that is off the axis perpendicular to the inspection surface, the accuracy of shape inspection by the shape sensor can be prevented from decreasing due to the influence of specular reflection or diffuse reflection of the inspection light on the inspection surface, and the accuracy of front / back discrimination can be improved.

[0021] When the object has a cylindrical shape with a hollow portion connecting the front and back end faces, and the shape inspection light is irradiated onto an area including the edge of the hollow portion, the shape sensor can simultaneously acquire information about the inspection surface, which is the end face of the cylindrical shape, as well as information about the shape near the edge of the hollow portion. By using information about the shape near the edge of the hollow portion to determine whether the object is front or back, the accuracy of the front / back determination can be improved compared to when only information about the height distribution of the inspection surface is used. In particular, when different structures, such as chamfered structures or stepped structures, are formed near the edge of the hollow portion, this information can be effectively used to determine whether the object is front or back.

[0022] In a case where the front / back discrimination device further includes a positioning member, located to the side of the introduction path in a region including the inspection position, capable of contacting the inspection surface of the object and having a slit through which the shape inspection light can pass, and a pressing member, located opposite the positioning member across the introduction path, capable of moving back and forth toward the introduction path and capable of pressing the object, whose rolling has been stopped by the stopping member, against the positioning member by advancing toward the introduction path, the pressing member presses the object against the positioning member, positioning the inspection surface at a position where it abuts against the surface of the positioning member. Then, shape inspection light is irradiated through the slit in the positioning member to inspect the inspection surface, thereby maintaining a constant positional relationship between the shape sensor and the inspection surface, enabling high-precision inspection. Even if the thickness of the object (the distance between the front and back end faces) changes, the position of the inspection surface remains constant, eliminating the need for precise adjustment of the positional relationship between the shape sensor and the inspection surface.

[0023] The front / back discrimination device further includes two introduction control members spaced apart along the introduction path upstream of the inspection position of the introduction path, the two introduction control members being capable of moving independently from the sides of the introduction path toward the introduction path, and when advanced, contacting the side of an object rolling along the introduction path to stop the object from rolling. If there is a distance between the two introduction control members that allows only one object to be placed therebetween, when determining the front / back of multiple objects, by controlling the advance and retreat of the introduction control members, one object to be inspected can be placed at the inspection position and inspected while the next object to be inspected waits between the two introduction control members, and then introduced to the inspection position after the inspection of the previous object is completed. By using such control, it is possible to introduce multiple objects into the inspection position and determine their front / back in an orderly and continuous manner.

[0024] If the front / back discrimination device further has a reversing unit that can change the orientation of the object so that the end faces of the front and back face face in a certain direction based on the discrimination result by the discriminating unit, the orientations of multiple objects can be aligned by arranging the objects in a predetermined orientation based on the result of the front / back discrimination. Then, for example, in the next process, processing can be performed correctly on a predetermined surface of the front or back face.

[0025] In this case, the reversing section is located downstream and above the stopping member along the introduction path, and the introduction path is movable up and down, so that when it is moved downward, the object can be held in the inspection position, and when it is moved upward, the object can be introduced into the reversing section by rolling.By moving the introduction path up and down, the rolling of the object due to gravity can be utilized to automatically place the object in the inspection section and move the object to the reversing section after inspection. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a plan view showing an outline of the configuration of a front / back discrimination device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a side view showing an outline of the front / back discriminating device. [Figure 3] 1A and 1B are side views showing the state near the inspection position in the front / back discrimination device, where FIG. 1A is a view seen from the irradiation side (-y side) of the shape inspection light, and FIG. 1B is a view seen from the introduction path side (+y side). [Figure 4] 4A and 4B are cross-sectional views illustrating a state in which a shape inspection light and a displacement measurement light are irradiated onto an object. [Figure 5] 10A and 10B are side views illustrating holding an object at an inspection position and irradiating it with light for shape inspection when the outer diameters of the objects are different. [Figure 6] 1A and 1B are diagrams showing an example of an object for which the front and back sides are to be discriminated using a front and back discrimination device, in which (a) is a cross-sectional view and (b) is a perspective view. [Figure 7] 10A is a diagram illustrating the irradiation state of light for shape inspection and FIG. 10B is a diagram illustrating the height distribution obtained when inspecting the shape of the back surface. [Figure 8] 1A and 1B are diagrams illustrating the irradiation state of light for shape inspection and the height distribution obtained when inspecting the shape of a surface. [Figure 9] FIG. 10 is a diagram illustrating distance measurement by a displacement sensor. [Figure 10] 10A and 10B are diagrams illustrating the supply of an object to a front / back discrimination device using an elevator device. [Figure 11] FIG. 10 is a diagram showing the results of inspection by a shape sensor. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, a front / back discrimination device 1 according to one embodiment of the present invention will be described with reference to the drawings. The front / back discrimination device 1 according to this embodiment is a device for discriminating the front / back of an object having front and back end surfaces.

[0028] [Example of object] Before describing the front / back discrimination device 1, the configuration of the object (workpiece) W to be discriminated as to whether it is front or back will be described. FIG.

[0029] The workpiece W has end faces W1 and W2 at both ends of the side surface W3. That is, it has a columnar or cylindrical shape with a hollow portion connecting the end faces W1 and W2. The columnar and cylindrical shapes also include disk and ring shapes with relatively small thicknesses.

[0030] Of the two end faces W1, W2 of the workpiece W, one is the front face W1 and the other is the back face W2. The front face W1 and the back face W2 are different from each other in at least one of their shapes and dimensions. Here, this not only refers to a configuration in which the front face W1 and the back face W2, which are flat end faces exposed at both ends of the workpiece W, are different in at least one of their shapes and dimensions, but also includes a configuration in which the workpiece W is different in at least one of its shapes and dimensions when observed from the outside, facing the end faces W1, W2. In other words, if a step structure or a chamfered structure (W5 to W7 in Figure 6) is formed on the outer peripheral edge (edge ​​on the side face W3 side) or inner peripheral edge (edge ​​on the hollow portion side) of the end faces W1 and W2, or if the inner peripheral face W4 has a slope, and the structure of the boundary between the end faces W1 and W2 and the side face W3 or inner peripheral face W4, or the sloped structure of the inner peripheral face W4, can be observed when the end faces W1 and W2 are viewed from the outside (when the front face W1 is viewed from above and the back face W2 is viewed from below in Figure 6), then this also includes forms with different shapes and dimensions for these structures.

[0031] As described above, the workpiece W has a front surface W1 and a back surface W2 that differ in at least one of their shapes and dimensions. However, because the workpiece W is introduced into a predetermined position in the front / back discriminating device 1 by utilizing the rolling of the workpiece W on its side surface W3, it is preferable that the side surface W3 of the workpiece W have a shape that allows it to easily roll down an inclined surface. In other words, it is preferable that the cross section of the workpiece W, including both end surfaces W1 and W2, has a shape that can approximate a figure with an outwardly convex curve, such as a circle or ellipse, a polygon, or a figure combining these. A shape that can approximate a cylinder or a tube (including a disk or ring) is most preferable. The material of the workpiece W is also not particularly limited as long as it does not deform due to rolling or the like and reflects the light (shape inspection light L1 and displacement measurement light La, Lb) used in the inspection for front / back discrimination. Examples of suitable materials include metal and hard resin materials.

[0032] The following description focuses on determining whether a workpiece W is made of steel and has a generally cylindrical shape, as shown in FIG. 6 . Here, the workpiece W has an annular front surface W1 and a back surface W2. However, the front surface W1 has a larger outer diameter than the back surface W2. A step structure W7, whose cross-sectional outer diameter changes, is formed on the side surface W3 between the front surface W1 and the back surface W2 along the thickness axis W8 of the workpiece W. Furthermore, the chamfered structures W5 and W6 formed at the junctions between the front surface W1 and the back surface W2 and the inner peripheral surface W4 are also different in shape. That is, the chamfered structure W5 on the front surface W1 side and the chamfered structure W6 on the back surface W2 side are inclined surfaces joining the front surface W1 and the back surface W2 and the inner peripheral surface W4, respectively. However, the widths of the chamfered structures W6 and W7 are different, i.e., a and b (a > b). Such a workpiece W can be manufactured, for example, by forging steel.

[0033] [Elevator device configuration] Here, we will briefly explain the elevator device 5 shown in Figure 10 as an example of a device for supplying a workpiece W having a surface W1 and a back surface W2 that differ in at least one of shape and dimension as described above to the front / back discrimination device 1.

[0034] The elevator device 5 has a conveyor 51 having a transport path that slopes upward from below, and a hopper 55 that can store the workpieces W. The lower end of the conveyor 51 is provided inside the hopper 55, and the conveyor 51 rises up the slope so as to rise from inside the hopper 55. A large number of workpieces W are stored in the hopper 55 in a random arrangement.

[0035] On the conveying surface of the conveyor 51, a number of loading plates 54 made of plate material are provided at intervals along the movement direction of the conveyor 51, on which the workpieces W can be placed one by one on their side surfaces W3. One end of the loading plates 54 faces one side edge of the conveyor 51, and the end on that side edge side is inclined downward. Furthermore, the elevator device 5 is provided with wall surfaces 52a, 52b on both sides of the conveyor 51 that rise up relative to the conveying surface of the conveyor 51 to prevent the workpieces W placed on the loading plates 54 from falling off. However, on the side of the side edge facing the lower end of the loading plates 54, an opening 53 where the wall surface 52a is not installed is provided in part.

[0036] An introduction path 11 of the front / back discriminating device 1 is arranged outside the opening 53, extending laterally. As will be described in detail later, the introduction path 11 is formed as an inclined surface extending from above to below, and its upper end 11a is provided close to the opening 53 of the elevator device 5.

[0037] When a large number of workpieces W are randomly arranged in the hopper 55 and the conveyor 51 is moved upward, the workpieces W stored in the hopper 55 are latched onto the placement plates 54 and transported upward by the conveyor 51. At the beginning of the transport, due to factors such as gravity and interference between the workpieces W, one workpiece W is placed on each placement plate 54, with its side surface W3 facing up. At this time, either the front surface W1 or the back surface W2 is in contact with the transport surface of the conveyor 51. The workpieces W placed on the placement plates 54 are placed on the lower side of the inclined placement plate 54 due to gravity, but are transported upward without falling off due to contact with the wall surface 52a. When the transported workpieces W reach the height where the opening 53 is provided, the wall surface 52a is discontinued, and they begin to roll along the inclined placement plate 54 due to gravity. Since the introduction path 11 of the front / back discriminating device 1, which will be described later, faces the side of the opening 53, the workpieces W that have rolled along the slope of the mounting plate 54 leave the mounting plate 54 and move into the introduction path 11. By this movement, the workpieces W are introduced into the front / back discriminating device 1 one by one.

[0038] As described above, when the workpiece W is placed on the placement plate 54 of the elevator device 5 from the hopper 55, the side surface W3 comes into contact with the placement plate 54 and one of the front and back end surfaces W1, W2 comes into contact with the conveying surface of the conveyor 51. However, the arrangement of the front and back surfaces, i.e., which of the front surface W1 and the back surface W2 comes into contact with the placement surface of the conveyor 51, varies randomly from workpiece to workpiece. Then, when the workpiece W rolls through the opening 53 and moves to the introduction path 11 of the front / back discrimination device 1, the arrangement of the front and back surfaces of the workpiece W does not change from the orientation in which it was placed on the placement plate 54. Therefore, the arrangement of the front and back surfaces of the workpiece W moved to the introduction path 11 of the front / back discrimination device 1, i.e., whether the front surface W1 and the back surface W2 face left or right with respect to the extending direction of the introduction path 11, varies randomly from workpiece to workpiece.

[0039] [Configuration of the front / back discrimination device] Next, the configuration of a front / back discrimination device 1 according to one embodiment of the present invention will be described. As described above, the front / back discrimination device 1 determines which side of the front / back surface W1 or W2 faces for a workpiece W having a front surface W1 and a back surface W2 that are different in at least one of shape and size, and then aligns the front and back surfaces in a predetermined direction based on the result of the determination.

[0040] The front / back discriminating device 1 can be disposed in various manufacturing processes for various articles, and the details of the manufacturing process are not limited. For example, the front / back discriminating device 1 can be disposed between a forging device and a rolling device that processes steel material, and the front / back of a substantially cylindrical workpiece W manufactured by the forging device is discriminated, and the workpiece W is supplied to the rolling device after the front / back directions are aligned. The following description will be given assuming such a configuration. In this case, the workpiece W manufactured by the forging device is stored in the hopper 55 of the elevator device 5, and as described above, the conveyor 51 supplies the workpiece W to the introduction path 11 of the front / back discriminating device 1 with the front / back directions randomized.

[0041] 1 and 2 show an outline of the front / back discriminating device 1. In addition, FIGS. 3 to 5 show the state of the front / back discriminating device 1 near the inspection position.

[0042] The front / back discrimination device 1 has an introduction unit 10 for introducing and arranging the workpiece W at a predetermined inspection position P, which includes an introduction path 11, a stopping member 12, a positioning member 13, a pressing member 14, and an introduction control unit 15. The front / back discrimination device 1 also has an inspection unit 20, which performs inspection at the inspection position P to obtain information that serves as the basis for distinguishing between the front and back of the workpiece W, and which includes a shape sensor 21 and a displacement sensor group 22. The front / back discrimination device 1 also has a discrimination unit (not shown) for distinguishing between the front and back of the workpiece W based on the information obtained by the inspection using the shape sensor 21 and the displacement sensor group 22. The front / back discrimination device 1 also has a reversing unit 30 equipped with a reversing unit 31 for changing the arrangement of the front and back of the workpiece W based on the results of the front / back discrimination.

[0043] (Introduction unit) As described above, the introduction unit 10 has an introduction path 11, a stopping member 12, a positioning member 13, a pressing member 14, and an introduction control unit 15, and functions to introduce the work W to an inspection position P where it can be inspected by the inspection unit 20.

[0044] The introduction path 11 is formed as a slope that slopes downward. Hereinafter, in this specification, the slope direction of the introduction path 11 is referred to as the x direction, and the width direction is referred to as the y direction. The direction perpendicular to the slope (xy plane) is referred to as the z direction.

[0045] As described above, the upper end 11a of the introduction path 11 faces the opening 53 of the elevator device 5, and the workpieces W are supplied one by one from the elevator device 5 through the opening 53. When the workpiece W is introduced into the upper end 11a of the introduction path 11, the side surface W3 contacts the surface of the introduction path 11, and the thickness direction axis W8 connecting both end surfaces W1, W2 faces in the width direction (y direction) of the introduction path 11. However, which side in the width direction the front surface W1 and the back surface W2 face varies randomly for each individual workpiece.

[0046] The workpiece W supplied to the upper end 11a of the lead-in path 11 rolls downward along the inclined direction (x direction) in the lead-in path 11 due to the action of gravity. Lead-in path walls 16a, 16b are erected on both sides of the lead-in path 11 in the width direction as wall surfaces to prevent the workpiece W from falling and significant displacement in the width direction. Note that the lead-in path walls 16a, 16b are not shown in the side view of Figure 2.

[0047] The introduction path 11 is movable up and down in a direction perpendicular to the inclined surface (z direction) independently of the stopping member 12. The inclination of the introduction path 11 does not change before, during, or after the up and down movement.

[0048] A plate- or block-shaped stopping member 12 is provided at the end of the lower end 11b of the introduction path 11 along the inclination direction. When the introduction path 11 is positioned downward within its movable range (as shown in FIGS. 1 and 2), the workpiece W that has rolled along the introduction path 11 and reached the lower end 11b abuts on the surface of the stopping member 12 at its side W3. The abutment with the stopping member 12 stops the rolling of the workpiece W, and the workpiece W comes to a standstill. The height (dimension in the z direction) of the stopping member 12 is set so that the workpiece W can be switched between a stationary state and a rolling state by the vertical movement of the introduction path 11. In other words, when the introduction path 11 is positioned lower within its movable range, the stopping member 12 abuts against the workpiece W and can hold the workpiece W at a predetermined inspection position P set at the lower end 11b of the introduction path 11, whereas when the introduction path 11 is positioned higher within its movable range, the stopping member 12 does not abut against the workpiece W and does not prevent the workpiece W from rolling further beyond the lower end 11b of the introduction path 11.

[0049] In this way, by configuring the inclined introduction path 11 to roll the workpiece W using gravity and stopping the rolling with the stopping member 12, the workpiece W can be automatically and quickly introduced to a predetermined inspection position P where inspection by the inspection unit 20 is possible, and subjected to inspection by the inspection unit 20. Even when multiple workpieces W are inspected sequentially by the inspection unit 20 and their front and back sides are determined based on the inspection results, the introduction of the workpieces W to the inspection position P and the subsequent inspection process can be carried out accurately and efficiently. By utilizing the rolling of the workpieces W, the connection between the previous and next processes, that is, the supply of the workpieces W from the elevator device 5 to the introduction path 11 and the movement of the workpieces W from the introduction path 11 to the reversing unit 30 can be smoothly performed.

[0050] Furthermore, by making the stopping member 12 that stops the workpiece W at the predetermined inspection position P a simple structure that prevents the workpiece W from rolling by abutting against the side surface W3 of the workpiece W, it becomes possible to stop the workpiece W at the predetermined inspection position P and perform inspection using the inspection unit 20 even if the outer diameter of the workpiece W changes due to a change in the type (product number) of the workpiece W, etc. In FIG. 5, two types of outer diameters of the workpiece W are shown by two circles with different diameters, and in either case, the workpiece W is held at a position where the side surface W3 abuts against the stopping member 12. As a result, as long as the irradiation range of the shape inspection light L1, which will be described later, is sufficiently secured, it becomes possible to perform inspection using the shape inspection light L1 while the workpiece W is placed at the predetermined inspection position P, even if the outer diameter of the workpiece W changes.

[0051] The accuracy and efficiency of placing the workpiece W at the inspection position P are further improved by the introduction unit 10 having a positioning member 13 and a pressing member 14. The positioning member 13 is provided along the introduction path 11 in an area including the inspection position P, and is made of a plate-like member erected against the inclined surface of the introduction path at a position on one outer side in the width direction of the introduction path 11 (the -y direction in the figure). The positioning member 13 may be provided continuous with one introduction path wall 16b or integral with the introduction path wall 16b. The plate surface of the positioning member 13 has an arrangement and dimensions that allow it to abut against one end face Wa (front surface W1 or back surface W2) of the workpiece W whose rolling has been stopped by the stopping member 12.

[0052] The positioning member 13 has slits 13a formed by partially removing a plate material constituting the positioning member 13. The shape and arrangement of the slits 13a are set so that a predetermined portion to be subjected to shape inspection on an inspection surface Wa, which is the surface on which shape inspection is performed by a shape sensor 21 described later, among the end faces W1, W2 of the workpiece W is exposed through the slits 13a, and shape inspection light L1 emitted from the shape sensor 21 passes through the slits 13a and is irradiated onto the portion to be inspected.

[0053] Here, it is preferable to set the shape and position of the slit 13a so that the inspection surface Wa of the workpiece W to be discriminated against, i.e., the outer and inner diameters of the front surface W1 and back surface W2, can contact the plate surface of the positioning member 13 and the area to be inspected can be exposed through the slit 13a even if the shape of the inspection surface Wa of the workpiece W to be discriminated against changes within an expected range due to changes in the type of workpiece W, etc. In the illustrated embodiment, the slit 13a is formed as a substantially parallelogram-shaped cutout that is inclined with respect to the x and z directions from the upper end to the lower end of the positioning member 13. As a result, for the expected workpiece W, the range from the outer periphery to the inner periphery of the inspection surface Wa is exposed through the slit 13a, making it possible to inspect it using the shape sensor 21. By making the length of the slit 13a (the length of the oblique side 13b inclined relative to the x- and z-directions) sufficiently long and by making the angle of the slit 13a (the angle of the oblique side 13b relative to the z-direction) sufficiently large, it is possible to expose the range from the outer periphery to the inner periphery of the inspection surface Wa through the slit 13a, even if the outer diameter or inner diameter of the inspection surface Wa varies to some extent. The specific angle of the oblique side 13b can be adjusted to the angle (θ) of the shape inspection light L1 irradiated onto the inspection surface Wa (see FIG. 5).

[0054] The pressing member 14 is provided opposite the positioning member 13 across the width direction of the introduction path 11. The pressing member 14 is provided as a rod-shaped member that protrudes from the introduction path wall 16a on the opposite side to where the positioning member 13 is provided (the +y side in the drawing) toward the inside in the width direction of the introduction path 11 (the -y side). The pressing member 14 is connected to a cylinder 14a, and the pressing member 14 can be driven to move back and forth along the width direction of the introduction path 11 by the cylinder 14a.

[0055] When the pressing member 14 is retracted, it does not come into contact with the workpiece W in the introduction path 11. On the other hand, when the rolling of the workpiece W is stopped by the stopping member 12 and the pressing member 14 is advanced toward the introduction path 11, the tip of the pressing member 14 comes into contact with the end face Wb of the workpiece W, and the workpiece W can be pressed against the plate surface of the positioning member 13 at the opposite end face, which is the inspection surface Wa.

[0056] When the pressing member 14 is retracted, the workpiece W is rolled into the introduction path 11. The workpiece W reaches the lower end 11b of the introduction path 11 and is stopped by the stopping member 12. In this state, the pressing member 14 is advanced to press the workpiece W against the positioning member 13, thereby holding the workpiece W at the predetermined inspection position P. At this time, the end face of the workpiece W facing the positioning member 13 becomes the inspection surface Wa, and the inspection surface Wa is positioned at a position where it abuts the positioning member 13. This allows inspection of multiple workpieces W by the inspection unit 20 under stable conditions, with the inspection surface Wa positioned at a fixed position and the positional relationship between the inspection surface Wa and the shape sensor 21 maintained constant. Even if the shape of the workpiece W, i.e., the shape and dimensions of the front surface W1 and back surface W2, or the thickness t, changes, inspection can be performed under constant conditions without changing the position of the inspection surface Wa and its relationship to the shape sensor 21. This eliminates or simplifies the process of adjusting or changing the inspection conditions.

[0057] When multiple workpieces W are sequentially introduced and positioned at the inspection position P for inspection, the introduction unit 10 has an introduction control unit 15, which further improves the efficiency of introducing and inspecting the workpieces W. The introduction control unit 15 is located upstream of the inspection position P along the introduction path 11 and controls the introduction of the workpieces W one by one into the inspection position P. The introduction control unit 15 has a first introduction control member 15a and a second introduction control member 15b. The first introduction control member 15a and the second introduction control member 15b are each formed of a rod-shaped member that protrudes toward the inside of the introduction path 11 in the width direction. The first introduction control member 15a and the second introduction control member 15b are spaced apart from each other along the inclination direction of the introduction path 11. Here, the first introduction control member 15a is located upstream in the inclination direction, and the second introduction control member 15b is located downstream in the inclination direction. The separation distance between the first introduction control member 15a and the second introduction control member 15b is set to a distance that allows only one workpiece W to be placed between the first introduction control member 15a and the second introduction control member 15b, that is, to a distance that is greater than or equal to one time and less than two times the maximum outer diameter of the workpiece W.

[0058] The first introduction control member 15a and the second introduction control member 15b are connected to cylinders 15c and 15d, respectively, and the cylinders 15c and 15d can drive the first introduction control member 15a and the second introduction control member 15b to move forward and backward independently of each other along the width direction of the introduction path 11. When the first introduction control member 15a and the second introduction control member 15b are retracted, they do not come into contact with the workpiece W rolling through the introduction path 11. On the other hand, when they are advanced, they can abut against the side surface W3 of the workpiece W rolling through the introduction path 11, stopping the rolling of the workpiece W. Furthermore, sensors may be provided near the first introduction control member 15a and the second introduction control member 15b to detect whether the workpiece W has passed the positions of the introduction control members 15a and 15b.

[0059] When a large number of workpieces W are sequentially supplied to the introduction path 11 and a workpiece W is undergoing inspection by the inspection unit 20 at the inspection position P, for example, and it is necessary not to introduce a new workpiece W to the inspection position P, the upstream first introduction control member 15a is maintained in an advanced state. Then, when a state is reached where a new workpiece W can be placed on standby so that it can be introduced to the inspection position P, the downstream second introduction control member 15b is advanced. In this state, the first introduction control member 15a is retracted for the time it takes for one workpiece W to pass. After one workpiece W has passed, the first introduction control member 15a is advanced again. In this manner, as shown in FIGS. 1 and 2 , one workpiece W is accommodated between the first introduction control member 15a and the second control member and is placed on standby to be moved to the inspection position P, while the subsequent multiple workpieces W are stopped upstream of the first introduction control member 15a.

[0060] In this state, when it becomes necessary to introduce a new workpiece W into the inspection position P, such as when the inspection of the previously inspected workpiece W is completed and the workpiece W is removed from the inspection position P, the second introduction control member 15b is retracted. Then, one workpiece W that has been waiting between the first introduction control member 15a and the second introduction control member 15b is introduced into the inspection position P at the lower end 11b of the introduction path 11 by rolling. During this time, the first introduction control member 15a is kept in its advanced state. From this state, the second introduction control member 15b is again advanced and the first introduction control member 15a is retracted, allowing the next workpiece W to wait.

[0061] By repeating such forward and backward movements of the first introduction control member 15a and the second introduction control member 15b, when a large number of works W are sequentially supplied to the introduction path 11, the works W can be introduced one by one in an orderly manner and with minimal delay to the inspection position P, where they can be subjected to inspection by the inspection unit 20. This makes it possible to efficiently distinguish between the front and back sides of a large number of works W.

[0062] (Inspection unit) The inspection unit 20 has two types of optical sensors: a shape sensor 21 and a displacement sensor group 22 .

[0063] The shape sensor 21 is a sensor that can detect the height distribution (distribution of unevenness) on the inspection surface Wa of the workpiece W over a predetermined inspection area by irradiating the inspection surface Wa of the workpiece W with shape inspection light L1 and detecting the shape inspection light L1 reflected by the inspection surface Wa. The shape of the inspection area is not particularly specified as long as it is not point-like but spreads over a certain range, but a known line sensor that uses a linearly spread laser beam as the shape inspection light L1 can be used as the shape sensor 21 to set the inspection area in a line.

[0064] Meanwhile, the displacement sensors constituting the displacement sensor group 22 can measure the distance from the emission surface to the measurement points by irradiating measurement points set in a point-like manner on the side surface W3 of the workpiece W with displacement measurement light and detecting the light reflected at the measurement points. A known distance measuring sensor using a point-like laser beam can be used as the displacement sensor. A plurality of displacement sensors are provided as a set, and each measures the distance to a plurality of measurement points spaced apart from each other along the thickness axis W8 on the side surface W3 of the workpiece W. That is, the side surface W3 of the workpiece W at the inspection position P is irradiated with displacement measurement light at a plurality of positions spaced apart from each other along the width direction (y direction) of the introduction path 11 to measure the distance. In this embodiment, two displacement sensors 22a and 22b are provided as a set, and two displacement measurement lights La and Lb are irradiated to two measurement points on the side surface W3 of the workpiece W to measure the distance.

[0065] The inspection unit 20 further has a discrimination unit that processes information obtained through inspection by the shape sensor 21 and the displacement sensor group 22. The discrimination unit is composed of an arithmetic and control device such as a computer, and receives information related to the inspection results from the shape sensor 21 and the displacement sensor group 22. The discrimination unit then processes the information to discriminate between the front and back sides of the workpiece W, that is, to determine whether the inspection surface Wa located on the positioning member 13 side (-y side) is the front surface W1 or the back surface W2. The discrimination result is then sent to the subsequent reversal unit 30. Furthermore, the inspection unit 20 preferably has a light-shielding member (not shown) that covers the periphery of the shape sensor 21 and the displacement sensor group 22 to reduce the influence of external light on the inspection results.

[0066] As shown in FIGS. 1 to 3, the shape sensor 21 is disposed outside the positioning member 13 in the width direction of the guide path 11 (in the −y direction in the drawing). Shape inspection light L1 emitted from the shape sensor 21 passes through a slit 13a provided in the positioning member 13 and is irradiated onto the inspection surface Wa of the workpiece W located at the inspection position P. The specific inspection area on the inspection surface Wa that is irradiated with the shape inspection light L1 and subjected to shape inspection is not particularly limited, but it is preferable to include as much as possible an area where a large difference in shape appears between the front surface W1 and the back surface W2. In particular, by setting the inspection area to include not only the inspection surface Wa, which is the end face of the cylindrical shape W of the workpiece W, but also the inner and outer peripheries that join the inspection surface Wa to the side surface W3 and inner circumferential surface W4, information about the shapes near the inner and outer peripheries can also be used to distinguish between the front and back sides. As shown in Fig. 6, when the inner peripheral edges of the front and back end faces W1 and W2 have different structures, such as chamfered structures W5 and W6, on the front and back sides, or when the inner diameters are different on the front and back sides, it is preferable to include the inner peripheral edges in the inspection area. Furthermore, when the outer peripheral edges of the front and back end faces W1 and W2 have different structures, such as chamfered structures, on the front and back sides, or when the outer diameters are different on the front and back sides, it is preferable to include the outer peripheral edges in the inspection area. In the illustrated embodiment, as shown particularly in Figs. 3(a) and 4, a linear shape inspection light L1 is irradiated onto an area including both the outer peripheral edge and the inner peripheral edge.

[0067] As long as the shape sensor 21 can be positioned at a predetermined inspection area on the inspection surface Wa of the workpiece W and the reflected light can be detected, the position of the shape sensor 21 and the irradiation angle of the shape inspection light L1 are not particularly limited. However, to prevent specular and diffuse reflection from the inspection surface Wa from deteriorating the accuracy of height distribution detection on the inspection surface Wa and the accuracy of front / back discrimination based on the detection results, it is preferable to position the shape sensor 21 away from the front of the slit 13a of the positioning member 13 and to set the irradiation angle of the shape inspection light L1 away from the axis (y direction) perpendicular to the inspection surface Wa. In the illustrated embodiment, the shape sensor 21 is positioned behind (-x side) and below (-z side) the slit 13a, and the shape inspection light L1 is irradiated from behind and below the inspection surface Wa in an obliquely incident position. Setting the deviation of the irradiation angle from the axis perpendicular to the inspection surface Wa to, for example, 10° or more effectively suppresses the effects of specular and diffuse reflection.

[0068] By irradiating the inspection surface Wa with the linear shape inspection light L1 from directions inclined in the forward / backward direction (x direction) and the upward / downward direction (z direction), as shown in FIG. 5, the direction of the shape inspection light beam L1 irradiated onto the inspection surface Wa is angled with respect to the x and z directions. As shown by the circles in the figure, regardless of the outer diameter of the workpiece W, the workpiece W is held in a position abutting the stopping member 12. Therefore, the smaller the outer diameter of the workpiece W, the further forward in the x direction (+x side) and downward in the z direction (-z side) it is held. Therefore, if the beam L1 irradiated onto the inspection surface Wa were parallel to either the x or z direction, the beam L1 would likely not hit the inspection surface Wa when the outer diameter of the workpiece W changed. However, because the beam L1 is angled with respect to the x and z directions on the inspection surface Wa, the beam L1 is more likely to hit the inspection surface Wa when irradiated with the shape inspection light L1 under the same conditions, regardless of the outer diameter of the workpiece W. In particular, if the angle of the beam L1 relative to the x-direction on the inspection surface Wa (θ in the figure) is set to 45°, the beam L1 can be irradiated in the diametric direction across the center or at a position and angle close to that, regardless of the outer diameter, on the cylindrical workpiece W abutting against the stopping member 12. This makes it easier for the beam L1 to be irradiated at the appropriate position even if the outer diameter of the workpiece W changes. Generally, this effect can be achieved by setting the angle θ within the range of 45°±10°. The length of the linear beam L1 irradiated on the inspection surface Wa (c in the figure) should be set so as to include the area from the outer periphery to the inner periphery on the inspection surface Wa of the workpiece W with the largest possible outer diameter.

[0069] 7 and 8, the inspection results of the front surface W1 and the back surface W2 of the workpiece W' will be described. The workpiece W' in question has a slightly different shape from the workpiece W shown in FIG. 6. Specifically, the front surface W1 and the back surface W2 have the same outer diameter, and the side surface W3 is a straight cylinder without a stepped structure. Meanwhile, the inner diameter is not constant along the thickness direction. On the back surface W2 side, the inner peripheral surface W4 is a straight cylinder and extends in a direction perpendicular to the back surface W2. On the front surface W1 side, the inner peripheral surface W4 slopes inward as it moves away from the front surface W1. In addition, both the front surface W1 and the back surface W2 have chamfered structures on their inner peripheral edges, but the chamfered structure W6 on the back surface W2 side joins the flat surface of the back surface W2 and the inner peripheral surface W4 with a single inclination, whereas the chamfered structure W5 on the front surface W1 side joins the flat surface of the front surface W1 and the inclined inner peripheral surface W4 with a gently curved surface.

[0070] Consider the case where such a workpiece W' is irradiated with shape inspection light L1 from an angle corresponding to the front (90° direction) of the inclined surface of the chamfered structure W6 on the back surface W2, as shown in Fig. 7(a). Shape inspection light L1 is also irradiated from the same direction on the front surface W1 side, as shown in Fig. 8(a). In this case, the angle of shape inspection light L1 with respect to the inclined inner circumferential surface W4 on the front surface W1 side is approximately 45°.

[0071] Figures 7(b) and 8(b) show schematic diagrams of the in-plane height distributions obtained based on the detection results of the reflected shape inspection light L1 for the back surface W2 and the front surface W1, respectively. Comparing the height distributions, the behavior of the height distributions on the front surface W1 and the back surface W2 is significantly different in the region toward the inner periphery (right side of the figure). On the back surface W2 side, the flat surface and the inner periphery W4 are joined via a single inclined surface, and the inner periphery W4 has a straight cylindrical shape. Therefore, in the height distribution, the height decreases rapidly in the region toward the inner periphery. In contrast, on the front surface W1 side, the flat surface and the inner periphery W4 are joined via a gently curved surface, and the inner periphery W4 has an inclined surface. Therefore, in the height distribution, the height decreases gradually in the region toward the inner periphery.

[0072] The height distribution information obtained by the shape sensor 21 is sent to the discrimination unit and used as the basis for distinguishing between the front and back sides. For example, height distribution data obtained for each of the front and back sides W1 and W2 of the target workpiece W is stored in the discrimination unit as reference data, and the height distribution data obtained for the inspection surface Wa of the workpiece W whose front and back sides are unknown is compared with the reference data for the front and back sides. Depending on which data is similar, it can be determined whether the inspection surface Wa is the front side W1 or the back side W2. Note that if the acquired height distribution data is significantly different from either the reference data for the front side W1 or the back side W2, it can be deemed indistinguishable. This indicates a defect in the inspection by the shape sensor 21 or a defective workpiece W.

[0073] The displacement sensor group 22 is arranged on the opposite outer side (+y direction in the drawing) from where the shape sensor 21 is arranged in the width direction of the introduction path 11. The two displacement sensors 22a, 22b are arranged next to each other so that they can irradiate point-like displacement measurement lights La, Lb to a plurality of measurement points (two points in this case) spaced apart along the thickness direction axis W8 on the side surface W3 of the workpiece W and measure the distances to those measurement points, respectively.

[0074] 9 shows an example of inspection of the side surface W3 of the workpiece W by the displacement sensor group 22 and the results thereof. The target workpiece W here is the same as that shown in FIG. 6, and has a step structure W7 on the side surface W3 due to the change in outer diameter between the front surface W1 and the back surface W2.

[0075] Assume that distance measurements are performed by irradiating displacement measurement light La and Lb from displacement sensors 22a and 22b to a first measurement point M1 located in an area with a larger cross-sectional outer diameter on the front surface W1 side of the side W3 of the workpiece W, and a second measurement point M2 located in an area with a smaller cross-sectional outer diameter on the back surface W2 side. The distances to the first measurement point M1 and the second measurement point M2 are D1 and D2, respectively, from a reference position S established parallel to the thickness axis W8 of the workpiece W. D1 is smaller than D2. The difference between distances D1 and D2 corresponds to the height (unevenness difference) of the step structure W7 on the side W3 of the workpiece W. Note that Figure 9 shows a configuration in which two displacement sensors 22a, 22b are installed side by side on the side of the workpiece W, and displacement measurement lights La, Lb are irradiated from the front onto the side surface W3 of the workpiece W. However, even when the displacement measurement lights La, Lb are incident on the side surface W3 of the workpiece W from an oblique angle, as shown in Figures 1 and 4, by setting the reference position S parallel to the thickness direction axis W8 of the workpiece W, the difference in distances measured for the two measurement points M1, M2 can be associated with the unevenness difference of the step structure W7 or the like on the side surface W3.

[0076] The distance information (D1, D2) measured by the two displacement sensors 22a, 22b is input to the discrimination unit and used to discriminate between the front and back sides. When the workpiece W is at the inspection position P, it can be determined that the front side W1 is located on the side where the shorter distance (D1) is measured along the width direction of the lead-in path 11, and the back side W2 is located on the side where the longer distance (D2) is measured along the width direction of the lead-in path 11. In other words, when one displacement sensor 22b measures the shorter distance (D1) at a position on the side where the positioning member 13 is provided along the width direction of the lead-in path 11 (the -y side), it can be determined that the inspection surface Wa abutting the positioning member 13 is the front side W1. When the other displacement sensor 22a measures the longer distance (D2) at a position on the opposite side (the +y side) of the positioning member 13 along the width direction of the lead-in path 11 from where the positioning member 13 is provided, it can be determined that the inspection surface Wa abutting the positioning member 13 is the back side W2. If the measured distances at the two measurement points M1 and M2 or their difference do not match, regardless of whether the inspection surface Wa is the front surface W1 or the back surface W2, it can be considered as indistinguishable. This indicates a defect in the inspection by the displacement sensor group 22 or a defective product of the workpiece W.

[0077] In the front / back discrimination device 1 according to this embodiment, the inspection means constituting the inspection unit 20 are optical sensors, such as a shape sensor 21 and a displacement sensor group 22, and perform non-contact inspection. This eliminates the need for precise alignment of each individual workpiece W, as is the case when using contact sensors. In particular, by using the shape sensor 21, which can measure the height distribution over a predetermined area rather than a single point, front / back discrimination can be performed based on the height distribution information within the inspection area, which extends over a predetermined area, by comparing it with reference data. Because more information is available than when inspecting a single point, even if there is a slight deviation in the positioning of the inspection surface Wa due to misalignment of the workpiece W or changes in the size or shape of the workpiece W, this effect can be reduced, allowing for accurate front / back discrimination. Furthermore, by using the shape sensor 21, which can acquire height distribution information over a predetermined inspection area, in combination with the introduction unit 10 described above, accurate and efficient positioning of the inspection surface Wa can be performed, while also acquiring accurate height distribution information and discriminating between the front and back.

[0078] Even if only the shape sensor 21 is used as the optical sensor included in the inspection unit 20, it is possible to accurately and efficiently determine whether the workpiece W is front or back based on information about the height distribution on the inspection surface Wa. However, by using the displacement sensor group 22 in combination, the accuracy of front / back determination can be further improved. The shape sensor 21 inspects the inspection surface Wa, which is the end surface of the workpiece W, while the displacement sensor group 22 inspects the side surface W3 of the workpiece W. Therefore, by using two types of sensors in combination, it is possible to use both the features on the end surfaces W1 and W2 of the workpiece W and the features on the side surface W3 to more accurately determine whether the workpiece is front or back than when using only one of them. The displacement sensor group 22 performs measurements at measurement points set discretely on the side W3 of the workpiece W, and has less information than the shape sensor 21, which performs inspection over an inspection area that is spread over a predetermined range. In addition, the measurement accuracy is easily affected by misalignment of the workpiece W and changes in the size and shape of the workpiece W. However, by using multiple displacement sensor groups 22 to measure the distance to multiple measurement points on the side W3 and evaluating the relationship between the measured distances, the influence of these factors can be reduced and the accuracy in distinguishing between the front and back can be improved.

[0079] When the inspection unit 20 has both the shape sensor 21 and the displacement sensor group 22, inspection is performed on a certain workpiece W using both types of sensors 21, 22, and the results are combined to determine the front and back of the workpiece W. For example, if the result of the front / back determination by the shape sensor 21 and the result of the front / back determination by the displacement sensor group 22 match, the determination result is adopted as the final determination result, but if the two determination results do not match, it is possible to consider a combined use in which the determination is deemed inaccurate and the determination is redone or it is concluded that determination is impossible.

[0080] Alternatively, the shape sensor 21 and the displacement sensor group 22 may be used depending on the type of workpiece W. The shape sensor 21 can sensitively detect differences in the shape and dimensions of the end faces W1 and W2 on the front and back sides of the workpiece W, while the displacement sensor group 22 can sensitively detect the dimensional distribution on the side face W3 of the workpiece W. Therefore, depending on the specific shape of the workpiece W, the sensor to be used can be selected depending on whether the difference between the front and back sides is more apparent on the end faces W1 and W2 or the side face W3. For example, in the workpiece W shown in FIG. 6, the difference between the front and back sides is clearly apparent on both the end faces W1 and W2 and the side face W3, so both the shape sensor 21 and the displacement sensor group 22 can be effectively used to distinguish between the front and back sides. On the other hand, in the workpiece W' shown in FIGS. 7 and 8, the difference between the front and back sides is clearly apparent on the end faces W1 and W2, such as the shape of the chamfered structures W5 and W6 on the inner peripheral edges and the presence or absence of inclination of the inner peripheral face W4. However, the side face W3 has a simple cylindrical shape, making it difficult to distinguish between the front and back sides. In such a case, it is difficult to distinguish between the front and back sides from the information of the displacement sensor group 22, but by using the shape sensor 21, it is possible to appropriately distinguish between the front and back sides.

[0081] In the above-described embodiment, even if the type (product number) of the workpiece W supplied to the front / back discrimination device 1 may change, it is assumed that the type of workpiece W being inspected is known to the discrimination unit through information transmission from an upstream processing process, etc. The front / back discrimination is performed by comparing the reference data measured and stored for the front and back end faces W1 and W2 of the known workpiece W with the data actually acquired by the shape sensor 21 and the displacement sensor group 22. However, if the shape sensor 21 and the displacement sensor group 22 can perform high-precision measurements, it is possible to determine the type of workpiece W based on the information obtained by the shape sensor 21 and the displacement sensor group 22, and then determine the front / back, even if the type of workpiece W is not known. For example, by comparing the height distribution pattern on the inspection surface Wa obtained by the shape sensor 21 and the information regarding the relationship between the distance measurements and multiple measurement points on the side surface W3 obtained by the displacement sensor group 22 with known data for multiple types of candidate workpieces W, it is possible to determine which of the candidate workpieces W is being supplied to the front / back discrimination device 1. Furthermore, when determining whether the workpiece is front or back, the data acquired by the shape sensor 21 and the displacement sensor group 22 can be used as is, or the data can be used to determine whether the workpiece is front or back after appropriate corrections have been made for errors and noise that occur in the data due to non-essential factors such as misalignment of the workpiece W at the inspection position P or the influence of external light.

[0082] (reversal unit) The workpiece W, whose front and back sides have been determined by the inspection unit 20, is moved to the reversing unit 30, where its position is changed depending on the determination result. The reversing unit 30 has a reversing section 31, a carrying-out path 34, and a reversing control section (not shown).

[0083] The reversing unit 31 has a base 32 and a turntable 33 that can rotate within the plane of the base 32. The reversing unit 31 is provided on the downstream side (+x side) and above (+z side) of the introduction path 11 with respect to the stopping member 12.

[0084] The reversing control unit receives the result of front / back discrimination from the discrimination unit of the inspection unit 20, and can rotate the turntable 33 of the reversing unit 31 by a predetermined angle based on that information. The discrimination unit can be configured with an arithmetic and control device such as a computer, and the discrimination unit and the reversing control unit may be provided as a common arithmetic and control device.

[0085] The discharge path 34 has a slope that allows the workpiece W to roll. The upper end of the slope is connected to the reversing unit 31, and the lower end of the slope is connected to a device in the next process after the front / back discriminating device 1, such as a rolling device. The slope of the discharge path 34 extends in a direction at an angle of 90° to the slope of the lead-in path 11.

[0086] When the inspection unit 20 has completed the front / back determination of the workpiece W placed at the inspection position P, the introduction path 11, which is configured to be able to move up and down, rises. The position of the lower end 11b of the introduction path 11 passes the upper end of the stopping member 12, and the workpiece W starts to roll along the introduction path 11. The rolling workpiece W reaches the upper surface of the reversing section 31. A stopper (not shown) is provided on the turntable 33, and the rolling of the workpiece W can be stopped by contact with the stopper.

[0087] When the rolling workpiece W stops on the turntable 33, the turntable 33 rotates, and the position of the workpiece W is changed. At this time, the rotation angle of the turntable 33 is determined by the rotation control unit based on the result of the front / back discrimination of the workpiece W transmitted from the discrimination unit. Specifically, the rotation angle is set to be 180° different when the discrimination unit determines that the inspection surface Wa of the workpiece W is the front surface W1 and when the discrimination unit determines that it is the back surface W2. As a result, the arrangement directions of the front and back end faces W1, W2 of the workpiece W rotated by the turntable 33 are aligned in a fixed direction, regardless of the front / back orientation before rotation. For example, if the inspection surface Wa is the front surface W1, the rotation angle is set to 90° counterclockwise in Figure 1, and if the inspection surface Wa is the back surface W2, the rotation angle is set to 270°.After being rotated by the turntable 33, whether the inspection surface Wa is the front surface W1 or the back surface W2, the front surface W1 of all workpieces W will face downstream of the introduction path 11 (+x direction).

[0088] In this way, the workpieces W whose front and back directions have been aligned by the reversing unit 31 are released from the stopper on the turntable 33 and begin to roll along the discharge path 34. As a result, all of the workpieces W roll along the discharge path 34 with their front and back directions aligned, and are supplied to the device for the next process. Since the front and back of the workpieces W are aligned, the processing of the next process, such as rolling, can be performed correctly on the specified surface of the front or back.

[0089] Although not shown in the drawings or described in detail, the front / back discrimination device 1 may have a discharge section branched off from the reversing section 31. As described above, if the inspection results obtained by the shape sensor 21 and the displacement sensor group 22 make it difficult to determine whether the workpiece W is facing front or back, the discrimination section can conclude that discrimination is impossible, which can be associated with an inspection defect or a defective product of the workpiece W. Such workpieces W whose front / back cannot be determined are preferably sorted to the discharge section and removed so as not to be supplied to the next process via the discharge path 34. For example, the discharge section may have a slope leading to the hopper 55 of the elevator device 5, and the removed workpieces W may be stored in the hopper 55. Such workpieces W are again supplied by the elevator device 5 to the front / back discrimination device 1 for front / back discrimination. If the reason the workpiece W was sorted to the discharge section as indistinguishable in the previous front / back discrimination was due to an accidental inspection defect by the inspection unit 20, a reinspection is likely to correctly determine the front / back. On the other hand, if the reason is a fundamental reason such as a product defect, there is a high possibility that the work W will be classified as indistinguishable even after a second inspection and will be sorted into the discharge section. Such work W will continue to circulate through the front / back discrimination device 1 and elevator device 5 via the discharge section, but the worker can remove it as appropriate after the front / back discrimination and inversion of other work W have been completed. [Example]

[0090] The present invention will be described in detail below using examples. Here, a shape sensor was used to measure the height distribution on the front and back surfaces of a substantially cylindrical workpiece, and it was verified whether it was possible to distinguish between the front and back surfaces.

[0091] As a sample, a roughly cylindrical workpiece having the shape shown in Figures 7 and 8 was manufactured by forging steel material. Then, in the same arrangement as shown in Figures 7 and 8, shape inspection light from the shape sensor was irradiated onto both the front and back end faces. The angle (θ) of the linear shape inspection light beam with respect to the inclination direction of the introduction path was set to 45°, and the shape inspection light was irradiated onto the area from the outer periphery to the inner periphery of both the front and back end faces.

[0092] The measurement results of the height distribution obtained for the front surface (W1) and the back surface (W2) are shown in Figure 11. These can be regarded as the actual measurement data corresponding to the height distributions shown schematically in Figure 8(b) and Figure 7(b).

[0093] The measurement results in Figure 11 show a significant difference between the front and back surfaces in the region near the inner periphery, indicated by the rectangle in the figure. Specifically, in the height distribution on the back surface, the measured height values ​​suddenly drop at a position relatively closer to the inner periphery (right side in the figure). In contrast, in the height distribution on the front surface, the drop begins relatively closer to the outer periphery (left side in the figure), but the peak where the drop begins is rounded, resulting in a gradual drop in height. This difference in behavior in the drop in height distribution can be attributed to the difference in the chamfered structure of the inner periphery on the back surface and the presence or absence of an inclination of the inner periphery. In other words, the chamfered structure on the back surface is formed by a single inclined surface, with a linear connection between the flat surface and the straight cylindrical inner periphery, while the chamfered structure on the front surface is formed by a curved surface, with a gradual connection between the flat surface and the inclined inner periphery.

[0094] As shown above, the measured height distribution data shows a significant difference between the front and back surfaces near the inner periphery. By focusing on this difference, it is possible to determine whether the edge being inspected is the front or back surface.

[0095] Although the embodiments of the present invention have been described above, the present invention is not particularly limited to these embodiments and various modifications can be made. [Explanation of symbols]

[0096] 1. Front and back discrimination device 10 Introductory Unit 11 Introductory path 12 Stop member 13 Positioning member 13a Slit 13b Hypotenuse of the slit 14 Pressing member 15 Introduction control section 15a first introduction control member 15b second introduction control member 16a, 16b Entry wall 20 Inspection Unit 21 Shape sensor 22 Displacement sensors 22a, 22b Displacement sensor 30 Reversing Unit 31 Reversal section 33 Turntable 34 Export path 5 Elevator equipment 51 Conveyor 53 Opening 54 Loading plate 55 Hopper L1 Shape inspection light La, Lb Displacement measurement light W,W' Work W1 surface W2 back W3 side W4 Inner surface W5 Chamfered surface structure W6 Chamfered structure on the back side W7 step structure W8 thickness direction axis Wa Inspection surface Wb End face opposite to inspection surface

Claims

1. a shape sensor for performing shape inspection of an object having front and back end faces at both ends of a side surface that are different from each other in at least one of shape and size, by irradiating a shape inspection light onto an inspection surface selected as one of the end faces and detecting the shape inspection light reflected from the inspection surface, thereby detecting a height distribution on the inspection surface over a predetermined inspection area on the inspection surface; an introduction path having a slope for rolling the object on the side surface to an inspection position where the shape inspection by the shape sensor can be performed; a stopping member located below the slope of the introduction path, which comes into contact with the object rolling along the introduction path and stops the rolling of the object at the inspection position; a discrimination unit that discriminates whether the inspection surface is a front or rear end surface based on information about a height distribution on the inspection surface obtained by the shape inspection; a displacement sensor that irradiates a plurality of measurement points spaced apart from each other on the side surface of the object at the inspection position with displacement measurement light and measures the distance to each of the plurality of measurement points, A front / back discrimination device characterized in that the discrimination unit is able to use information on the relationship between the distances measured by the displacement sensor for each of the measurement points when determining whether the inspection surface is a front or back end surface.

2. 2. The apparatus according to claim 1, wherein the shape sensor irradiates the shape inspection light onto the inspection surface of the object at the inspection position from a direction deviated from an axis perpendicular to the inspection surface.

3. the object has a cylindrical shape having a hollow portion connecting the front and back end surfaces, 3. The apparatus for distinguishing between front and back sides according to claim 1, wherein the shape inspection light is irradiated onto an area including an edge of the hollow portion.

4. a positioning member that is disposed on a side of the introduction path in an area including the inspection position, that can come into contact with the inspection surface of the object, and that has a slit through which the shape inspection light can pass; The front / back discrimination device according to any one of claims 1 to 3, further comprising a pressing member that is arranged at a position opposite the positioning member across the introduction path, is capable of moving back and forth toward the introduction path, and by moving forward toward the introduction path, can press the object, whose rolling movement has been stopped by the stopping member, against the positioning member.

5. a shape sensor for performing shape inspection of an object having front and back end faces at both ends of a side surface that are different from each other in at least one of shape and size, by irradiating a shape inspection light onto an inspection surface selected as one of the end faces and detecting the shape inspection light reflected from the inspection surface, thereby detecting a height distribution on the inspection surface over a predetermined inspection area on the inspection surface; an introduction path having a slope for rolling the object on the side surface to an inspection position where the shape inspection by the shape sensor can be performed; a stopping member located below the slope of the introduction path, which comes into contact with the object rolling along the introduction path and stops the rolling of the object at the inspection position; a discrimination unit that discriminates whether the inspection surface is a front or rear end surface based on information about a height distribution on the inspection surface obtained by the shape inspection; a positioning member that is disposed on a side of the introduction path in an area including the inspection position, that can come into contact with the inspection surface of the object, and that has a slit through which the shape inspection light can pass; a pressing member that is arranged at a position opposite the positioning member across the introduction path, that is capable of moving back and forth toward the introduction path, and that, by moving forward toward the introduction path, can press the object, whose rolling has been stopped by the stopping member, against the positioning member.

6. the front / back discrimination device further includes two introduction control members provided along the introduction path at a distance from each other on the upstream side of the inspection position of the introduction path, the two introduction control members are capable of advancing and retreating independently from each other from the sides of the introduction path toward the introduction path, and when advanced, come into contact with the side surfaces of the object rolling in the introduction path to stop the rolling of the object, 6. The front / back discriminating device according to claim 1, wherein a distance is provided between the two introduction control members such that only one of the objects can be placed therebetween.

7. The front / back determining device further includes an inverting unit, The front / back discrimination device according to any one of claims 1 to 6, characterized in that the inversion unit is capable of changing the orientation of the object so that the end surfaces of the front and back are oriented in a fixed direction based on the result of discrimination by the discrimination unit.

8. the inverting portion is provided downstream and above the stopping member along the introduction path, The front / back discrimination device according to claim 7, characterized in that the introduction path is movable up and down, and when moved downward, the object can be held at the inspection position, and when moved upward, the object can be introduced into the reversing section by rolling.

9. a shape sensor for performing shape inspection of an object having front and back end faces at both ends of a side surface that are different from each other in at least one of shape and size, by irradiating a shape inspection light onto an inspection surface selected as one of the end faces and detecting the shape inspection light reflected from the inspection surface, thereby detecting a height distribution on the inspection surface over a predetermined inspection area on the inspection surface; an introduction path having a slope for rolling the object on the side surface to an inspection position where the shape inspection by the shape sensor can be performed; a stopping member located below the slope of the introduction path, which comes into contact with the object rolling along the introduction path and stops the rolling of the object at the inspection position; a discrimination unit that discriminates whether the inspection surface is a front or rear end surface based on information about a height distribution on the inspection surface obtained by the shape inspection; an inverted portion; the reversing unit is provided downstream and above the stopping member along the introduction path, and is capable of changing the direction of the object based on the result of the determination by the determining unit so that the front and back end surfaces face in a certain direction; The introduction path is movable up and down, and when moved downward, the object can be held at the inspection position, and when moved upward, the object can be introduced into the reversal section by rolling.

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